Variable pitch propeller with emergency control

ABSTRACT

A variable-pitch propeller has a pair of fixed pistons in the hub thereof, and a cylinder hydraulically movable on these fixed pistons and connected to the blades to vary the pitch of the blades. One of the fixed pistons is hollow and contains an auxiliary piston movable under the influence of a separate hydraulic system into engagement with the cylinder so that if the first hydraulic system fails, the auxiliary system can at least get the ship to port. The auxiliary hydraulic system can include a separate passage through the propeller shaft, or a branch from the lubricant passage through the propeller shaft.

Merkx et al.

ilnited States Patent 1191 VARIABLE PITCH PROPELLER WITH EMERGENCY CONTROL [75] Inventors: Antonius N. Merkx; Hubertus P. van

Spijk, both of Drunen, Netherlands [73] Assignee: Lips N. V. Drunen, Drunen,

Netherlands [22] Filed: Aug. 23, 1972 [21] Appl. No.: 282,904

[30] Foreign Application Priority Data 3/1970 Haglund etal. "41 6/157 [1 1 3,802,800 451 Apr. 9', 1974 2/l972 Liaaen 416/157 Primary Examiner-Everette A. Powell, Jr. Attorney, Agent, or FirmYoung and Thompson 5 7 ABSTRACT A variable-pitch propeller has a pair of fixed pistons in the hub thereof, and a cylinder hydraulically movable on these fixed pistons and connected to the blades to vary the pitch of the blades. One of the fixed pistons is hollow and contains an auxiliary piston movable under the influence of a separate hydraulic system into engagement with the cylinder so that if the first hydraulic system fails, the auxiliary system can at least get the ship to port. The auxiliary hydraulic system can include a separate passage through the propeller shaft, or a branch from jthe lubricant passage through the propeller shaft.

4 Claims, 3 Drawing Figures 'PATENTED APR 9 1974 sum 2 or 3 VARIABLE PITCH PROPELLER WITH EMERGENCY CONTROL The present invention relates to a variable-pitch propeller for a ship, more particularly a variable-pitch propeller with emergency control for a ship with a hydraulic main system located within the hub of the propeller for adjusting the pitch of the propeller blades and comprising a movable hydraulic cylinder cooperating with one or more stationary pistons and connected with the blades via mechanisms, whereby the emergency con trol is formed by an auxiliary piston which is hydraulically independent from the main'system. Such a propeller is commonly known. According to a preferred known embodiment the movable hydraulic cylinder consists of an axially moving yoke with pins, acting in slots of the blade flanges for adjustment of the blade pitch. The yoke is hollow and contains two coaxial cylinder compartments separated by a central wall; Each cylinder compartment cooperates with a stationary piston fixedly mounted in the hub. Medium such as oil is supplied to the cylinder compartments through a system of two coaxial pipes located in the hollow propeller shaft, the outer pipe being fixed in the shaft and the inner one being movable axially within the hollow shaft and being connected to and opening through the separation wall in the yoke, the two pipes communicating respectively with the cylinder compartments.

An oil supply sleeve is arranged around the propeller shaft in the vicinity of the ends of the oil pipes remote from the hub. For adjusting the pitch of the blades, oil is supplied to or discharged from one of the cylinder compartments in the yoke through the inner pipe, whilst oil is discharged from or supplied to the other cylinder compartment through the annular space between the two pipes. In this way the yoke is moved and the propeller blades are rotated in order to adjust the pitch. In such a propeller, if the oil supply system fails or if the movable pipe is defective, it becomes impossible to adjust and to hold the blades. Moreover, the blades will then be pushed in the astern position as a result of the shape of the blades, so that the ships propulsion has to be stopped.

An emergency control for a variable-pitch propeller using an auxiliary piston'secured to the movable oil supply pipe and using the latter as a mechanical connection member has been already proposed. However, with such an arrangement, if the pipe breaks, the emergency control can not be used. Moreover, the pipe has to be made as a heavy structure, because it must be able to withstand great mechanical holding force for the blades.

According to the present invention, the auxiliary piston is located within the hub concentrically arranged within a stationary piston of the main system, which stationary piston is made hollow, whereby the emergency control takes place by direct contact between auxiliary piston and movable cylinder of the main system if medium under pressure is supplied to one side of the auxiliary piston.

The hollow fixed piston of the main system acts as a cylinder for the auxiliary piston.

This emergency system has various advantages. Firstly, the auxiliary piston is arranged within the hub without using additional space. The auxiliary piston is normally stationary, thus no wear of its seals occurs.

- There is a direct contact with the movable main cylinder, and no reliance on the movable pipe. There is great blade adjusting capacity and holding capacity, because the auxiliary piston may have a large diameter, so that low control pressures can be used.

According to a preferredembodiment of the invention the medium under pressure is supplied to the auxiliary piston via the channel in the propeller shaft, which during normal operation of the propeller is employed for supplying and discharging lubrication oil from a supply tank to and from the bearings of the blades and the mechanisms connecting the movable cylinder with the blades, whereby in this channel near the end remote from the hub a manually operated valve is arranged and in this channel near the end adjacent the hub an automatically operated valve. is arranged (FIG. 3). The respective valves are necessary to prevent oil from flowing away to the supply tank for the lubrication oil and to prevent the bearings of the blades and the mechanisms connecting the cylinder of the main system with the blades from being subjected to high pressure.

According to a second embodiment of the invention,

the medium under pressure is, supplied to the auxiliary piston via a separate channel in the propeller shaft with a supply opening in the outer wall of the propeller shaft remove from the hub (FIGS. 1 and 2 For emergency control the propeller shaft has to be stopped and the supply opening of the channel has to be connected with a source for medium under pressure.

According to a third embodiment of the invention, around the supply opening a separate medium supply sleeve is arranged, surrounding the propeller shaft (FIG. 2). In this way the emergency control can operate without stopping the propeller shaft.

In the drawings three specific embodiments are shown by way of example.

FIG. 1 is a longitudinal section of an embodiment using a separate oil channel through the propeller shaft connecting the main cylinder with the blades is employedto actuate the emergency control.

In FIG. 1 the propeller shaft l is connected with the propeller hub 2 by means not shown. The blades 3 are rotatable with respect to the hub 2 about radial axes via mechanisms 4 connecting the blades 3 to a movable yoke 4a. This yoke 4a is hollow and contains two cylinder compartments within its cylindrical walls 5 and '6, the two compartments being separated by a transverse central wall 7. The walls 5 and 6 cooperate with stationary pistons 8 and 9 either fixed to the hub 2, or forming integral parts respectively of the hub 2 and the propeller shaft 1.

One end of a pipe 10 is fixed to the transverse wall 7. This pipe 10 is movable in axial direction of the shaft 1 and extends through the wall 7, opening into the cylinder 5. At its other end the pipe 10 is guided by a throat 11. Around the pipe 10 a second pipe 12 is arranged, which pipe 12 is fixed in the propeller shaft 1. The outer pipe 12 projects into the interior of the cylinder 6. The two pipes and 12 extend coaxially within the hollow shaft 1. p

ln this way two channels are formed, a channel 13 within the pipe 10 and a channel 14 between the pipes Y10 and '12, for supplying and discharging oil or other liquid under pressure to and/or from each of the workingchambers on both sides of the wall 7 of the yoke.

. The oil or other pressure fluid is supplied to the hub annular channel around the fixed tube 12. This channel 20 is connected with a channel 21 leading to the interior of the hub. This system is used for lubricating the bearings of-the blades 3 and the mechanisms 4.

- The second oil line 22 leads from a pump (not shown) to an annular channel 23 in the sleeve 15. A radial channel 24 in the shaft 1 debouchesinto this annular channel 23. The radial channel 24 is connected with the annular channel 14 between the pipes-10 and 12.

The third oil line 25 leads from a pump (not shown) to an annular channel 26 in the sleeve 15. A radial channel 27 in the shaft 1 debouches in this annular channel 26. The radial channel 27 is connected with a chamber 28 in the shaft 1. This chamber is connected with the channel 13 through the movable pipe 10.

The oil sleeve is as usual provided with sealing means with the shaft 1. Such an oil supply sleeve is commonly known. 7

If oil is supplied through the line 22, the yoke 4a will be moved to the left in FIGJ; if oil is supplied through the line 25 the yoke 4a will be moved to the right.

The propeller is provided with an emergency control. For this purpose an auxiliary piston 29 is housed within the fixed piston 9, which is hollow and acts as a cylinder for the auxiliary piston 29. The piston 29 is provided with sealing rings for sealing with respect to the inner surface of the piston 9, and with respect to the outer surface of the fixed tube 12.

A channel 30 in the shaft 1 leads from the interior, of the fixed piston 9 on the right-hand side of the auxiliary piston 29 to the outer surface of the shaft 1. A hose 31 can be connected with the outer end of the channel 29 by suitable connecting means (not shown).

If oil or other medium under pressure is supplied through the hose 31 the auxiliary piston 29 will move to the left with respect to the piston 9 andwith respect to the pipe 12. At a certain moment the left-hand end of the auxiliary piston 29 will engage and abut against the central wall 7 of the'yoke 4a and urge the yoke towards its extreme left-hand position. The pressure in the channel 30 and on the right-hand side of the piston 29 can be maintained by closing the end opening of the channel 30, and the hose 31 can be removed.

In this way the blades are placed in the forward position and maintained in this position.

Thus'if the main pitch control system fails, for instance by failing oil pressure or by damage to the movable pipe 10, the propeller shaft can be stopped, the hose 31 connected and the auxiliary piston 29 moved by supplying pressurized medium. After this the connection between the channel 30 and the hose 31 is closed and the hose 31 is removed. Then the shaft 1 can be started again.

In this way theship can reacha'harbour, where the main system can be'repaired.

The embodiment according to'FIG. 2 corresponds nearly completely to the embodiment according to FIG. 1, but here it is not necessary to stop the shaft 1 inorder to actuate the emergency control. The hose 31 is connected with a second stationary supply sleeve 32, having'an annular channel 33 and sealing means. In this way auxiliary medium under pressure can be supplied to the channel 30 without stopping the shaft 1.

The embodiment according to FIG. 3 lacks the channel 30. in this embodiment the channels 19 and 20 'of the lubricating system are also used for moving the auxiliary piston 29 to the left. Of course, arrangements have to be made in order to prevent the oil tank 17 and- /or the mechanisms 4 becoming pressurized, when the auxiliary piston has to be moved. For this purpose there is provided a manually-operated three-way valve 34 arranged in the channel 19 and an automatic non-return valve 35 in the channel 21.

If the piston 29 has to be moved, the shaft 1' is stopped and a hose (not shown) like the hose '31 is connected to a branch 19a of the channel 19. The valve 34 is set to a position such that there is a direct connection between the branch 19:: and the channel 20, and that the connection to the tank 17 is closed. Since the automatic valve 35 is closed ifa differential pressure is exerted on the underside of this valve (the side farthest from the interior of the hub), the medium under pressure will be supplied to the right-hand side of the auxiliary piston 29, to actuate the emergency control.

The valve 35 can be a normal non-return ball valve. For lubricating purposes no differential pressure is exerted on the lower side of the ball. Normally there is according to the present invention is that an indepen-.

dent source of pressure medium, for instance a hand pump, is used to actuate the emergency control. Further the movable tube 10 is not used for emergency control. Another important advantage is that the auxiliary piston is arranged in the'hub and does not move in normal pitch adjustments. Even if the sealing between the main cylinders and the main pistons is defective, the auxiliary piston can still be used.

The operative surfacea'rea of the auxiliary piston can be more than 50 percent of the operative-surface area of the main system, so that the auxiliary pressure need not be high.

What we claim is:

1. A variable-pitch propeller comprising a hub, a plurality of blades carried by the hub, at least one piston in the hub fixed relative to the hub, a hydraulic cylinder in the hub movable on said at least one piston relative to the hub, means for supplying medium to the cylinder to move the cylinder on said at least one piston relative to the hub, means interconnecting the cylinder and the blades to change .the pitch of the blades 'upon movement of the cylinder relative to the hub, a said piston being hollow, an auxiliary piston in said hub movable coaxially within and relative to said hollow piston, and means independent of the first-mentioned mediumsupplying means for supplying medium to said auxiliary piston to move said auxiliary piston into contact with said cylinder.

2. A variable-pitch propeller as claimed in claim 1, and a propeller shaft to which the hub is secured, said propeller shaft having a passageway therethrough for supplying and discharging lubrication oil from a supply tank to and from said interconnecting means, said passageway comprising said independent mediumsupplying means, a manually operated valve adjacent the end of said passageway remote from the hub, and

an automatically operated valve in said passageway adopening in the outer wall of said shaft remote from said hub.

4. A variable-pitch propeller as claimed in claim 3, and a separate medium-supply sleeve about the shaft and said supply opening. 

1. A variable-pitch propeller comprising a hub, a plurality of blades carried by the hub, at least one piston in the hub fixed relative to the hub, a hydraulic cylinder in the hub movable on said at least one piston relative to the hub, means for supplying medium to the cylinder to move the cylinder on said at least one piston relative to the hub, means interconnecting the cylinder and the blades to change the pitch of the blades upon movement of the cylinder relative to the hub, a said piston being hollow, an auxiliary piston in said hub movable coaxially within and relative to said hollow piston, and means independent of the first-mentioned medium-supplying means for supplying medium to said auxiliary piston to move said auxiliary piston into contact with said cylinder.
 2. A variable-pitch propeller as claimed in claim 1, and a propeller shaft to which the hub is secured, said propeller shaft having a passageway therethrough for supplying and discharging lubrication oil from a supply tank to and from said interconnecting means, said passageway comprising said independent medium-supplying means, a manually operated valve adjacent the end of said passageway remote from the hub, and an automatically operated valve in said passageway adjacent the hub.
 3. A variable-pitch propeller as claimed in claim 1, and a propeller shaft to which the hub is secured, said independent medium-supplying means comprising a separate passageway through said shaft with a supply opening in the outer wall of said shaft remote from said hub.
 4. A variable-pitch propeller as claimed in claim 3, and a separate medium-supply sleeve about the shaft and said supply opening. 